— Lily is a happy girl, but today she seems in a bad mood.
— Something ________ to her.
| A．must happen | B．should have happened |
| C．could have happened | D．must have happened |
6. The Olympic Games _____ held every _____ years.
| A．is; four | B．are; four | C．is; five | D．are; five |
5. About 40 _____ of the population of that country _____ on farms.
| A．percent; lives | B．percent; live | C．percents; live | D．percents; lives |
4. _____ can be done _____ been done.
| A．All; have | B．All that; have | C．All; has | D．All that; has |
3. He played on the _____ for two hours and when he returned he found half his goods _____ stolen.
| A．sand; were | B．sand; was | C．sands; were | D．sands; was |
2. The League secretary and monitor _____ asked to make a speech at the meeting.
| A．is | B．was | C．are | D．were |